None of my children were born when Muhammad Ali fought his last fight, a wretched parody - 'Drama in the Bahamas' - that spooled out in Nassau against Trevor Berbick 35 years ago. Yet news of his death seemed to register as some kind of precious light going out for even the youngest.

And his poetry outlives him.

"Float like a butterfly..." recited my 12-year-old almost absent-mindedly on hearing that he had passed away.

I asked her who she thought Muhammad Ali was. "A boxer, the greatest?" she responded quizzically.

Ali did not simply transcend boxing. He outgrew all conventional sense of what a sportsman (or woman) could rationally become.

And time softened all the harder edges of his story as it did with Nelson Mandela. People came to see in him some kind of beautiful expression of the human spirit. Ali won over everyone in the end; the opponents he goaded; the heavyweight American columnists so riled by that early braggadocio; the political system once straining to have him put in jail.

All came to see only the innate dignity of someone who refused to comply with the social or behavioural mores expected of a black man born into a segregated southern town. At the time, the then Cassius Clay was vilified for not knowing his place. But it turned out he knew it better than maybe any man alive.

Unmatched

The glamour of his era as a heavyweight champion of the world is probably unmatched in sport, let alone boxing. Back then, it consumed a global attention that seems scarcely credible in this age of lumbering strangers scuffling for such an assortment of belts, it becomes an intellectual feat to separate one from the other.

The world held its breath when Ali fought.

It felt on intimate terms with his life story, not to mention those of his most iconic opponents like Sonny Liston and Joe Frazier and George Foreman.

The great writers of the time followed Ali about like Pilot-fish, not simply for the dazzling cabaret of his personality, but for a sense of being at the epicentre of something epochal.

His story became a virtual screenplay through their words, right through to the last, blurred years of a life under attack from his embattled nervous system.

Ali's fourth wife, Lonnie, has described his joy at lighting the Olympic flame in Atlanta 20 years ago as "like he'd won the heavyweight title back a fourth time", yet, it was an image of profound sadness too in the loss it conveyed.

Ali seemed to have barely sufficient strength to hold the torch and looked faintly terrified that his own hands might betray him in front of three billion people watching. Here was a beautiful man left ravaged by a disease that many believe the ring may have inflicted upon him.

Maybe the only normal thing he did in boxing was stay too long.

The fights with Frazier especially took a great physical toll on Ali who described their third contest in Manila as reducing both of them to old men. "Closest I've come to death," he said.

That was in 1975, but Ali would have another ten professional fights, losing three of the last four. The night Berbick beat him, he was one month short of his 40th birthday. And, by then, everybody could see the sadness.

The showman who'd once bragged about wrestling with alligators, tussling with whales and handcuffing lightning had already lost much of the music within.

Maybe Hugh McIlvanney put the efficacy of a young, vibrant Ali best, when he wrote: "Pop singers and film actors can have young girls scrambling to touch them, but they don't make 16-stone building workers tighten at the throat and offer emotional declarations of faith."

That Muhammad Ali would shadow-box strangers in a public street. He once jumped out of a car in Queens having seen a truck driver changing a tyre, crept up upon the unsuspecting target and yelled, "I hear you're talking around town that you can whup me. Well, here I is!"

As George Plimpton wrote, the driver "seeing Muhammad and recognising him, his jaw dropped and he froze in a curious half-stoop, the tyre iron clattering from his hand."

Refusing

In his prime, Ali did not box for three-and-a-half years having been stripped of his title for refusing the US Army draft during the Vietnam War. He declared himself a conscientious objector and would deliver over 200 anti-war speeches whilst banned from his sport and facing a potential five-year jail sentence.

At the time, he was widely vilified through mainstream America for that stance, one borne - in many eyes from his alignment with The Black Muslims group.

But as the wretched human cost of that war became more and more evident to a shocked American public, so too the broader attitude towards Ali softened. In time, the US Supreme Court ruled that young men, opposed to the war on strong ethical grounds, should be exempted from the military draft.

Hindsight now ennobles Ali for his stance on Vietnam.

And, in the end, even US presidents came to regard him as the highest caste of human being, though the transformation required some time and healing. His money gone and engaged in a series of legal wrangles, Ali's first fight back after that ban (in 1970 against Jerry Quarry) was opposed by Georgia governor, Lester Maddox, who declared it "a day of mourning".

How good was Ali the boxer?

He beat Archie Moore, he beat Sonny Liston (twice), he beat Floyd Patterson (twice), he beat Frazier (twice), he beat George Foreman. The latter victory, quite literally, shocked the world given Foreman's brutal and brief destructions of Frazier and Ken Norton.

Moore, who was in Foreman's corner that night in Kinshasa, spoke of a genuine fear that his fighter might - literally - kill Ali in the ring.

And Ali did everything against Foreman that fight experts presumed he would have been counselled against. He invited the bigger man forward, just leaning back on the ropes with gloves to his head, elbows to his ribs, waiting for the storm to blow itself out. And that it did, a startled and exhausted Foreman counted out in the eighth.

Ninety-five per cent of boxing writers polled beforehand had predicted defeat for Ali. He had a perspective on what people expected of him that did not always sit easily with those in authority. Ali had described Africa as his "home" before that Foreman fight and it was a recurring theme of his.

In 1970, he castigated the US fight scene thus: "They don't look at fighters to have brains. They don't look at fighters to be businessmen, or human, or intelligent.

"Fighters are just brutes that come to entertain the rich white people. Beat up on each other and break each other's noses and bleed and show off like two little monkeys, killing each other for the crowd.

"And half the crowd is white. We're just like two slaves in that ring. The masters get two of us big old black slaves and let us fight it out while they bet; 'My slave can whup your slave!'

"That's what I see when I see two black people fighting."

It was a moral commentary often hard to reconcile with his own baiting of black opponents. Ali famously infuriated Frazier with his "Uncle Tom" jibes, but his dismissal of Liston had been even more tasteless.

"I'm gonna put that ugly bear on the floor," he declared before their fight in '64. "And, after the fight, I'm gonna build myself a pretty home and use him as a bearskin rug. Liston even smells like a bear. I'm gonna give him to the local zoo after I whup him."

Maybe his natural charm filtered that kind of abuse into something softer than it reads today. When he won light-heavy gold as an 18-year-old at the 1960 Olympics, fellow competitors proclaimed him Mayor of the athletes' village. Ali's personality, even then, had an unnatural wattage.

Everyone pretty much knew he was gone as a fighter maybe five years before he seemed to realise it himself.

Ken Norton broke his jaw in '76 and when Ali squared up to his old sparring partner, Larry Holmes, at Caesars' Palace in 1980, he did so in such wretchedly poor health that the fight should never have been sanctioned. Ali had been wrongly diagnosed with a thyroid disorder beforehand and was put on medication that left him hopelessly dehydrated and fatigued. On one morning run, he had to abort after a troubled half mile.

Slaughter

At ringside, Sylvester Stallone would describe the fight as "Like watching an autopsy on a man who's still alive."

Each judge awarded Holmes every round until the slaughter was stopped at the end of the tenth, by which time the winner was visibly backing away from inflicting unnecessary punishment on the old champion. It was subsequently discovered that the medication Ali was on that evening could have killed him.

He'd been partly to blame himself, vanity corrupting his thinking and his love of money (a reputed $8 million for that fight) inflating that same vanity. Afterwards, he admitted that he felt humiliated. "I felt embarrassed for all my fans," he said. "I fought like an old man who was washed up." That night, the world had seen a ghost.

Though illness would thieve his physical elegance in later years, it could never quite subdue the glow of Muhammad Ali. He became, perhaps, the best-loved human on the planet, that love transcending all race and colour, all national borders. There is a scene in 'When we were Kings' that shows Ali floating at his most beautiful.

In the build-up to the Foreman fight, his opponent is recorded punching holes in the heavy bag the size of water melons. "No-one ever hit the heavy-bag the way Foreman did," says Norman Mailer.

The camera cuts to Ali and he is dancing. Just scissoring his legs in that trademark shuffle and singing out his poetry to a besotted audience: "I'm young, I'm handsome, I'm pretty, I'm fast and I can't possibly be beaten." Mailer says he suspects Ali was "scared" at the time.